Stage apparatus and exposure apparatus provided with the stage apparatus

Abstract

A stage apparatus comprises a pedestal, an X axis guide bar which is fixed on the pedestal, an X stage which is movable along an upper surface of the pedestal and the guide bar, and a Y stage which is placed over the X stage and movable along the pedestal in a direction of the Y axis. Vacuum-pre-loadable static pressure air bearings, in which pressures of vacuum ports are independently controllable, are provided on a surface of the X stage opposing to the pedestal and on another surface of the X stage opposing to the X axis guide bar. By using the stage apparatus, the electric power consumption of driving means for movable units can be reduced, the amount of heat generation can be reduced, and the bearing gap, can be adjusted highly accurately after assembling.

What is claimed is: 
     
       1. A stage apparatus comprising: a pedestal;   at least one first guide bar which is fixed on the pedestal;   a first movable unit which is movable in a first direction along an upper surface of the pedestal and the first guide bar;   at least one motor for driving the first movable unit; and   a vacuum-pre-loadable static pressure air bearing comprising vacuum ports and gas-ejecting ports which are formed on a surface of the first movable unit opposing to the pedestal and on another surface of the first movable unit opposing to the first guide bar, wherein, during operation, pressures of the vacuum ports are independently controllable.   
     
     
       2. The stage apparatus according to claim 1, wherein the motor is a linear motor having a stator which is arranged in parallel to the first guide bar. 
     
     
       3. The stage apparatus according to claim 1, further comprising: a second guide bar placed on the first movable unit; and   a second movable unit movable along the second guide bar in a second direction perpendicular to the first direction,   said second movable unit comprising a vacuum-preloadable static pressure air bearing, said vacuum-pre-loadable static pressure air bearing being formed on a surface opposing to the pedestal.   
     
     
       4. The stage apparatus according to claim 3, further comprising linear motors having a pair of stators which are arranged in parallel to the second guide bar. 
     
     
       5. A stage apparatus comprising: a pedestal made of ceramic;   at least one first guide bar made of ceramic which is fixed on the pedestal;   a first movable unit which is movable in a first direction along an upper surface of the pedestal and the first guide bar;   at least one motor for driving the first movable unit; and   a vacuum-pre-loadable static pressure air bearing comprising first vacuum ports and first gas-ejecting ports which are formed on a first surface of the first movable unit opposing to the pedestal and on another surface of the first movable unit opposing to the first guide bar, wherein, during operation, pressures of the first vacuum ports formed on the first surface of the first movable unit are controlled independently of pressures of the first vacuum ports formed on the other surface of the first movable unit.   
     
     
       6. The stage apparatus according to claim 5, further comprising: a second guide bar placed on the first movable unit; and   a second movable unit movable along the second guide bar in a second direction perpendicular to the first direction,   said second movable unit comprising a vacuum-pre-loadable static pressure air bearing which includes a second vacuum port and a second gas-ejecting port, said vacuum-pre-loadable static pressure air bearing being formed on a surface opposing to the pedestal, said second movable unit further comprising third gas-ejecting ports, and said third gas-ejecting ports being formed so that the second guide bar is interposed therebetween, wherein a pressure of the second vacuum port is controllable independently of a pressure of the first vacuum port.   
     
     
       7. The stage apparatus according to claim 6, further comprising linear motors having a pair of stators which are arranged in parallel to the second guide bar for guiding the second movable unit in the second direction. 
     
     
       8. The stage apparatus according to claims 5, wherein the motor is a linear motor having a stator which is arranged in parallel to the first guide bar. 
     
     
       9. A stage apparatus comprising: a pedestal;   at least one first guide bar which is fixed on the pedestal;   a first movable unit which is movable in a first direction along an upper surface of the pedestal and the first guide bar;   at least one motor for driving the first movable unit; and   a vacuum-pre-loadable static pressure air bearing comprising a plurality of vacuum ports and a plurality of gas-ejecting ports which are formed on a surface of the first movable unit opposing to the pedestal and on another surface of the first movable unit opposing to the first guide bar, wherein during operation, pressures of the vacuum ports are independently controllable.   
     
     
       10. The stage apparatus according to claim 9, further comprising: a second guide bar which is placed on the first movable unit; and   a second movable unit movable along the second guide bar in a second direction perpendicular to the first direction,   said second movable unit comprising a vacuum-pre-loadable static pressure air bearing which includes a plurality of second vacuum ports and a plurality of second gas-ejecting ports, said static pressure air bearing being formed on a surface opposing to the pedestal, said second movable unit further comprising a plurality of third gas-ejecting ports on each of surfaces, and said plurality of third gas-ejecting ports being formed so that the second guide bar is interposed therebetween, wherein pressures of the second vacuum ports are controllable independently of pressure of the first vacuum ports.   
     
     
       11. A projection exposure apparatus for projecting a pattern on a mask onto a photosensitive substrate, comprising: a pedestal made of ceramic;   at least one first guide bar made of ceramic which is fixed on the pedestal;   a first movable unit which is movable in a first direction along an upper surface of the pedestal and the first guide bar;   at least one motor for driving the first movable unit; and   a vacuum-pre-loadable static pressure air bearing comprising vacuum ports and gas-ejecting ports which are formed on a surface of the first movable unit opposing to the pedestal and on another surface of the first movable unit opposing to the first guide bar, wherein, during operation, pressures of the vacuum ports formed on the first surface are controllable independently of pressures of the vacuum ports formed on the other surface.   
     
     
       12. The projection exposure apparatus according to claim 11, wherein the motor is a linear motor having a stator which is arranged in parallel to the first guide bar. 
     
     
       13. The projection exposure apparatus according to claim 11, further comprising: a second guide bar placed on the first movable unit; and   a second movable unit movable along the second guide bar in a second direction perpendicular to the first direction,   said second movable unit comprising a vacuum-pre-loadable static pressure air bearing, said vacuum-pre-loadable static pressure air bearing being formed on a surface opposing to the pedestal.   
     
     
       14. The projection exposure apparatus according to claim 11, further comprising linear motors having a pair of stators which are arranged in parallel to the second guide bar.